Synchronously Jacking Hydraulic System of Large Cross-section Box Tunneling

Abstract:

Different from anti-drag system （ADS）, front jacking （FJ） and endless self-advancing （ESA）, a new synchronously jacking hydraulic system is presented. Under the condition of non-artificial ground freezing, it can fulfill jacking operation before excavating operation. Three-level structure of the system improves reliability. A “double-object synchronization” control scheme of displacement synchronization and even-pressure enables groups of hydraulic cylinders to control the jacking speed and posture of box. The system is saving-energy. The features of antiinterferencing hardware circuits are presented also. And the system is applied successfully in Beihong Vehicular Undercrossing Tunnel project in Shanghai, China. The tunnel is 126.00m long, 34.20m wide, and 7.85m high. And the project itself is also the one constructed with the largest cross-section under shallow saturated soft clay formation in China.